Bath boilers and water heaters with bath boilers

Abstract

To provide a bath boiler which enables a water flow switch to stably operate even if a passage extending from a pump to the water flow switch bends.SOLUTION: A bath boiler includes a connection pipe part 70 which connects a pump with a water flow switch 40. A casing 71 of the water flow switch includes: an inflow pipe part 76 where hot water flows from the connection pipe part; and an outflow pipe part where which hot water flows out from the casing in a third direction orthogonal to the first direction. The inflow pipe part includes: a first cylinder part 76A; a second cylinder part 76B disposed at a downstream; and a third cylinder part 76C which connects the first and second cylinder parts. A cross sectional area of an interior of the second cylinder part is smaller than a cross sectional area of an interior of the first cylinder part. On an inner peripheral surface of the second cylinder part, an orthogonal surface orthogonal to a third direction is provided at an opposite side of the third direction. An inner peripheral surface of the third cylinder part is formed with a connection surface 81 which connects the orthogonal surface with an inner peripheral surface of the first cylinder part. The connection surface 81 is located at an inner side of the third cylinder part while continuously changing its facing direction from a direction opposite to the second direction to the third direction from the upstream to the downstream. An upstream side end of the connection surface is disposed at a depth side in the second direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a bath heater and a water heater with a bath heater. [Background technology]

[0002] A water flow switch described in Japanese Patent Application Laid-Open No. 2007-323934 (Patent Document 1 below) is known as a water flow switch used in a circulation heating path such as a bath reheating circuit. This water flow switch includes a casing that forms a fluid flow path therein, a magnetic body disposed in a detection chamber provided within the casing, a support formed of an elastic member that supports the magnetic body relative to the casing, and a reed switch fixed to the outside of the casing. When a water flow is generated in the detection chamber by a pump that circulates hot and cold water, the support elastically bends under the pressure of the flowing water. The bending of the support causes the magnetic body to swing within the detection chamber and approach the reed switch. The approach of the magnetic body closes the reed switch. When the reed switch is closed, the control unit detects the generation of a water flow in the reheating circuit and begins heating the hot and cold water. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-323934 Summary of the Invention [Problem to be solved by the invention]

[0004] Normally, the water flow switch is assumed to be located directly above the pump. In the configuration of Patent Document 1, the inflow passage that allows hot and cold water to flow into the detection chamber extends vertically, and the inflow direction of hot and cold water from the pump into the inflow passage is the same as the inflow direction of hot and cold water from the inflow passage into the detection chamber. This stabilizes the flow of hot and cold water in the detection chamber.

[0005] However, devices such as bath heaters that are equipped with water flow switches have many components. Therefore, depending on the layout of the components within the device, it may not be possible to place the water flow switch directly above the pump, and it may be necessary to place it diagonally above the pump. In such cases, it is possible to provide a flow path from the pump to the detection chamber with a connecting passage that extends horizontally and an inlet passage that extends upward from the end of the connecting passage.

[0006] When a horizontally extending connecting passage is connected to an inlet passage as described above, the inertia of the hot and cold water causes the hot and cold water to flow unevenly in an area of ​​the inlet passage away from the connecting passage, forming a swirling flow downstream of the inlet passage. As a result, the position where the hot and cold water hits the support body is unstable, which can cause the operation of the reed switch to become unstable.

[0007] The present disclosure was completed based on the above circumstances, and aims to provide a bath heater in which the water flow switch can operate stably even if the flow path from the pump to the water flow switch is curved. [Means for solving the problem]

[0008] The bath heater of the present disclosure is a bath heater installed in a circulation circuit through which hot and cold water circulates, and comprises: a pump that circulates hot and cold water in the circulation circuit; a water flow switch arranged in the circulation circuit and activated in response to water flow in a first direction; and a connecting pipe connecting the pump and the water flow switch. At the connection between the connecting pipe and the water flow switch, the direction of hot and cold water flow changes from a second direction intersecting the first direction to the first direction. The water flow switch comprises a casing that forms a path for hot and cold water, a detection piece that is swingably arranged in a detection chamber formed in the casing, a fixing member that fixes one end of the detection piece, and a reed switch that is fixed to the casing and closes when the detection piece approaches. The casing comprises an inlet pipe through which hot and cold water flowing in from the connecting pipe flows out into the detection chamber, and an outlet pipe through which hot and cold water flows out from the detection chamber in a third direction perpendicular to the first direction. the third direction intersects with the second direction, the inlet pipe comprises a cylindrical first tubular portion, a second tubular portion located downstream of the first tubular portion, and a third tubular portion connecting the first tubular portion and the second tubular portion and having a smooth inner circumferential surface, the cross-sectional area of ​​the internal space of the second tubular portion is smaller than the cross-sectional area of ​​the internal space of the first tubular portion, the inner circumferential surface of the second tubular portion has an orthogonal surface located opposite the third direction and perpendicular to the third direction, the orthogonal surface extends from the upstream end of the second tubular portion in the first direction, the inner circumferential surface of the third tubular portion has a connecting surface connecting the orthogonal surface to the inner circumferential surface of the first tubular portion, the connecting surface is located inside the third tubular portion while the facing direction of the connecting surface continuously changes from the direction opposite the second direction to the third direction as it moves from upstream to downstream, and the upstream end of the connecting surface is located at the far end of the inner circumferential surface of the third tubular portion in the second direction. [Effects of the Invention]

[0009] According to the present disclosure, a bath heater can be provided in which the water flow switch can operate stably even if the flow path from the pump to the water flow switch is curved. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic circuit diagram of a water heater with a bath heater according to an embodiment. [Figure 2] FIG. 2 is a perspective view of the pump, the water flow switch, and the connecting pipe portion. [Figure 3] FIG. 3 is a plan view of the pump, the water flow switch, and the connecting pipe section. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line BB in FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along CC in FIG. [Figure 7] FIG. 7 is a perspective view of the cross section DD in FIG. 6 as seen from below. [Figure 8] Figure 8 is a cross-sectional view showing cross sections of the inlet pipe section cut at different height positions. Figure 8(A) is a cross-sectional view taken along line DD in Figure 6. Figure 8(B) is a cross-sectional view taken along line EE in Figure 6. Figure 8(C) is a cross-sectional view taken along line FF in Figure 6. Figure 8(D) is a cross-sectional view taken along line GG in Figure 6. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0012] (1) The bath heater of the present disclosure is a bath heater installed in a circulation circuit through which hot and cold water circulates, and includes: a pump that circulates hot and cold water in the circulation circuit; a water flow switch arranged in the circulation circuit and activated in response to water flow in a first direction; and a connecting pipe connecting the pump and the water flow switch. At the connection between the connecting pipe and the water flow switch, the direction of hot and cold water flow changes from a second direction intersecting the first direction to the first direction. The water flow switch includes a casing that forms a path for hot and cold water, a detection piece that is swingably arranged in a detection chamber formed in the casing, a fixing member that fixes one end of the detection piece, and a reed switch that is fixed to the casing and closes when the detection piece approaches. The casing includes an inlet pipe through which hot and cold water flowing in from the connecting pipe flows out into the detection chamber, and an outlet pipe through which hot and cold water flows out from the detection chamber in a third direction perpendicular to the first direction. the third direction intersects with the second direction, the inlet pipe section comprises a cylindrical first tubular section, a second tubular section arranged downstream of the first tubular section, and a third tubular section connecting the first tubular section and the second tubular section and having a smooth inner circumferential surface, the cross-sectional area of ​​the internal space of the second tubular section is smaller than the cross-sectional area of ​​the internal space of the first tubular section, the inner circumferential surface of the second tubular section has an orthogonal surface arranged opposite the third direction and perpendicular to the third direction, the orthogonal surface extends from the upstream end of the second tubular section in the first direction, the inner circumferential surface of the third tubular section has a connecting surface connecting the orthogonal surface to the inner circumferential surface of the first tubular section, the connecting surface is located inside the third tubular section while the facing direction of the connecting surface continuously changes from the direction opposite the second direction to the third direction as it moves from upstream to downstream, and the upstream end of the connecting surface is arranged at the far end of the inner circumferential surface of the third tubular section in the second direction.

[0013] In the above configuration, hot water flows from the pump through the connecting pipe into the inlet pipe of the water flow switch. At the connection between the connecting pipe and the water flow switch, the flow direction of the hot water is shifted from the second direction to the first direction. Therefore, a swirling flow of hot water occurs at the connection between the connecting pipe and the water flow switch. The hot water that flows from the connecting pipe into the inlet pipe is shifted toward the back in the second direction and flows in the first direction within the first tubular part of the inlet pipe. Furthermore, the flow of hot water changes from the second direction to the third direction upstream and downstream of the water flow switch, which also creates a drift and swirling flow of hot water.

[0014] The inner peripheral surface of the third cylindrical portion is provided with a connecting surface that is positioned inward of the third cylindrical portion as it moves from upstream to downstream. This suppresses the swirling flow of hot and cold water as it flows in the first direction inside the third cylindrical portion. In addition, the cross-sectional area of ​​the internal space of the second cylindrical portion is smaller than the cross-sectional area of ​​the internal space of the first cylindrical portion. Therefore, the flow of hot and cold water is easily straightened as it passes through the interiors of the third and second cylindrical portions. This stabilizes the flow of hot and cold water in the detection chamber, allowing the hot and cold water pressure to be concentrated at a fixed position on the detection piece, resulting in stable operation of the water flow switch.

[0015] Furthermore, as the connecting surfaces move from upstream to downstream, the direction they face continuously changes from the direction opposite the second direction to the third direction, so that the pressure loss of hot water caused by flowing through the third tubular section can be minimized while rectifying the flow of hot water.

[0016] (2) It is preferable that the cross-sectional area of ​​the internal space of the second cylindrical portion is equal to or greater than half the cross-sectional area of ​​the internal space of the first cylindrical portion.

[0017] In the above configuration, the cross-sectional area of ​​the internal space of the second cylindrical portion is more than half the cross-sectional area of ​​the internal space of the first cylindrical portion, so that the second cylindrical portion and the third cylindrical portion can straighten the flow of hot water while reducing pressure loss of the hot water.

[0018] (3) The water heater with a bath heater disclosed herein is a water heater with a bath heater comprising the above-mentioned bath heater, a hot water supply circuit, and a burner that heats a bath heat exchanger provided in the circulation circuit and a hot water heat exchanger provided in the hot water supply circuit.

[0019] [Details of the embodiments of the present disclosure] Hereinafter, embodiments of the present disclosure will be described with reference to Figures 1 to 8. The present disclosure is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0020] [Overall structure of a water heater with a bath heater] FIG. 1 is a schematic circuit diagram of a water heater with a bath heater 1 including a bath heater 1A. The water heater with bath heater 1 has an inner body 2 housed in a housing (not shown) and has a hot water combustion chamber 4 and a bath combustion chamber 5 separated by a partition member 3, and a burner 6. The burner 6 includes hot water burners 6A, 6A·· disposed below the hot water combustion chamber 4 and a bath burner 6B disposed below the bath combustion chamber 5. Each combustion chamber 4, 5 is provided with an ignition plug 8 and a flame rod 9. A combustion fan 10 is provided below the inner body 2 to supply combustion air to each burner 6A, 6B.

[0021] A hot water supply primary heat exchanger 11 and a hot water supply secondary heat exchanger 12 (an example of a hot water supply heat exchanger) through which the combustion exhaust from the hot water supply burner 6A passes are provided at the top of the hot water combustion chamber 4. A bath primary heat exchanger 13 and a bath secondary heat exchanger 14 (an example of a bath heat exchanger) through which the combustion exhaust from the bath burner 6B passes are provided at the top of the bath combustion chamber 5. Each secondary heat exchanger 12, 14 is housed in an exhaust hood 15 provided at the top of the inner body 2. The exhaust hood 15 is formed with an exhaust port 16 through which the combustion exhaust that has passed through each secondary heat exchanger 12, 14 is discharged.

[0022] A gas pipe 17, which is connected to an external gas pipe, is connected to a gas inlet provided on the bottom of the housing. Gas branch pipes 18, 18... branching from the gas pipe 17 are connected to each of the hot water burner 6A and bath burner 6B, and each gas branch pipe 18 is provided with a gas solenoid valve 19 for opening and closing the gas flow path. In addition, a main gas solenoid valve 20 and a gas proportional valve 21 are provided upstream of the gas pipe 17 before branching.

[0023] A water supply pipe 22, which is connected to a water inlet on the bottom of the housing, is connected to the inlet of the heat absorption pipe of the hot water secondary heat exchanger 12. From upstream, the water supply pipe 22 is provided with a strainer 23 equipped with a drain plug, a hot water supply water volume sensor 24 that detects the volume of water flowing through the water supply pipe 22, a hot water supply water inlet thermistor 25 that detects the inlet water temperature, and a water volume control motor 26. The outlet of the heat absorption pipe is connected to the inlet of the heat transfer pipe of the hot water supply primary heat exchanger 11, and the outlet of the heat transfer pipe is connected to a hot water outlet pipe 27 that is connected to a hot water outlet on the bottom of the housing. The hot water outlet pipe 27 is provided with a hot water heat exchanger thermistor 28 that detects the outlet temperature from the hot water primary heat exchanger 11, and a hot water outlet thermistor 29 that detects the outlet hot water temperature from the appliance downstream of the hot water heat exchanger thermistor 28. A bypass pipe 30 that bypasses the hot water primary and secondary heat exchangers 11, 12 is connected between the upstream side of the hot water outlet thermistor 29 in the hot water outlet pipe 27 and the downstream side of the water volume control motor 26 in the water supply pipe 22, and a water distribution valve 31 that controls the bypass flow rate is provided in the bypass pipe 30. In this way, a hot water circuit A is formed within the housing, in which water from the water supply pipe 22 passes through the hot water secondary heat exchanger 12 and the hot water primary heat exchanger 11 in that order, is heated by heat exchange with the combustion exhaust of the hot water burner 6A, and then is discharged from the hot water outlet pipe 27.

[0024] Meanwhile, a return pipe 35 connected to the bath return port on the bottom of the housing is connected to the inlet of the heat absorption pipe of the bath secondary heat exchanger 14. The bath return port is connected to the bathtub 37 via an external return pipe 36. A pump 38 is provided downstream of the return pipe 35. A bath return thermistor 39 that detects the bath return temperature is provided upstream of the pump 38. A water flow switch 40 and a water level sensor 41 are provided downstream of the pump 38. The water flow switch 40 detects the flow of hot and cold water sent out from the pump 38 and activates the bath burner 6B. The detailed configuration of the water flow switch 40 will be described later. The outlet of the heat absorption tube of the bath secondary heat exchanger 14 is connected to the inlet of the heat transfer tube of the bath primary heat exchanger 13. The outlet of the heat transfer tube is connected to an inlet pipe 42 connected to the bath inlet on the bottom of the housing. The bath inlet is connected to the bathtub 37 via an external inlet pipe 43. The inlet pipe 42 is equipped with a bath inlet thermistor 44 that detects the bath inlet temperature.

[0025] In this way, within the housing, by operating the pump 38, hot water in the bathtub 37 passes from the return pipe 35 through the bath secondary heat exchanger 14 and the bath primary heat exchanger 13 in that order, where it is heated by heat exchange with the combustion exhaust from the bath burner 6B, and then returns to the bathtub 37 through the supply pipe 42, forming a bath circuit B (an example of a circulation circuit).

[0026] In the present disclosure, the bath heater 1A includes a hot water circulation path in the bath circuit B, from a return pipe 35 connected to the bath return port on the bottom of the housing to an outflow pipe 42 connected to the bath outflow port on the bottom of the housing. The bath heater 1A is connected to the bathtub 37 through external piping (external return pipe 36 and external outflow port 43). In other words, the bath circuit B, together with the external piping, forms a circulation circuit connecting the bathtub 37 and the bath heater 1A.

[0027] A drop pipe 45 is connected between the hot water outlet pipe 27 downstream of the bypass pipe 30 and the return pipe 35 upstream of the pump 38. This drop pipe 45 is provided with a drop water solenoid valve 46, which opens and closes the drop pipe 45, and a bath water volume sensor 47, which detects the amount of water flowing through the drop pipe 45, from the upstream side (hot water outlet pipe 27 side). Three check valves 48, 48, 48 are provided downstream of the bath water volume sensor 47. A cut-off valve 49 is connected between these check valves 48. This cut-off valve 49 is connected to a drain pipe 50 connected to an overflow port provided on the bottom of the housing and to an inlet pipe 51 connected to the water supply pipe 22 downstream of the strainer 23. When the internal pressure of the hot water in the drop pipe 45 increases due to the back pressure from the return pipe 35 and becomes greater than the back pressure from the inlet pipe 51, the cut-off valve 49 discharges the hot water that has flowed back from the drop pipe 45 to the overflow port via the drain pipe 50.

[0028] A neutralizer 55 is provided within the housing to neutralize the drain generated in the hot water secondary heat exchanger 12 and the bath secondary heat exchanger 14. This neutralizer 55 is connected to a drain receiver 56 provided on the bottom surface of the exhaust hood 15 via a drain inlet pipe 57, and is also connected to the drain pipe 50 of the isolation valve 49 via a drain outlet pipe 58. The neutralizer 55 is also provided with a water level electrode 59 for detecting the water level, and a drain outlet 60 for discharging the drain from the bottom surface of the housing.

[0029] Although not shown, the water heater with bath heater 1 is equipped with a controller that receives detection signals from various thermistors, sensors, etc. and operates various valves, etc. to control the outlet water temperature and fill the bathtub 37 with water, as well as a remote control that is connected to the controller so that it can communicate with the controller.

[0030] [Water flow switch, connecting pipe] As shown in Figure 2, the water flow switch 40 of this embodiment is connected to the discharge port 38B of the pump 38 via a connecting pipe 70. The suction port 38A of the pump 38 is connected to the bath return port. A pipe 78 is connected downstream of the water flow switch 40. As shown in Fig. 5, the connecting pipe 70 includes a first bent pipe 70A connected to the discharge port 38B of the pump 38, a straight pipe 70B extending horizontally from the first bent pipe 70A, and a second bent pipe 70C connecting the straight pipe 70B to the water flow switch 40. Each bent pipe 70A, 70C has a bent shape, with openings at both ends extending substantially vertically. At the connection between the connecting pipe 70 and the water flow switch 40 (the second bent pipe 70C in this embodiment), the flow direction of hot and cold water changes from the right in Fig. 5 (an example of the second direction) to upward (an example of the first direction).

[0031] As shown in Figure 4, the water flow switch 40 comprises a casing 71 through which hot and cold water flows, a detection piece 72 arranged within the casing 71, a fixing member 73 that fixes the rear end of the detection piece 72, and a reed switch 74 fixed to the casing 71.

[0032] The casing 71 is made of synthetic resin. The casing 71 includes a box-shaped casing body 71A and a lid 71B that closes the upper opening of the casing body 71A. A detection chamber 75 for detecting water flow is formed inside the casing 71. A fixing member 73 is formed to protrude downward from the underside of the lid 71B. The fixing member 73 is disposed at a rear position within the detection chamber 75. The reed switch 74 is fixed to a front position on the upper surface of the lid 71B. The casing body 71A includes an inlet pipe 76 that penetrates the bottom wall of the casing body 71A in the vertical direction, and an outlet pipe 77 that penetrates the front wall of the casing body 71A in the front-rear direction. The upper part of the inlet pipe 76 protrudes above the bottom wall of the casing body 71A. The upper end of the inlet pipe 76 is inclined downward as it extends forward. The outlet pipe 77 extends forward (an example of the third direction) and is connected to the inlet of the bath secondary heat exchanger 14 via piping 78.

[0033] The detection piece 72 includes an elastically deformable elastic piece 72A and a magnetic body 72B fixed to the front end of the elastic piece 72A. The rear end of the elastic piece 72A is fixed to a fixed member 73. The front portion of the elastic piece 72A is disposed facing the internal space of the second cylindrical portion 76B (inlet pipe portion 76B) so as to block the upper portion of the second cylindrical portion 76B. When hot or cold water flows into the detection chamber 75 from the inlet pipe portion 76, the elastic piece 72A is elastically deformed by the pressure from the hot or cold water, with the rear end fixed to the fixed member 73 as the base end. As a result, the front end of the elastic piece 72A moves upward so as to move away from the inlet pipe portion 76. As a result, the magnetic body 72B approaches the reed switch 74, switching the reed switch 74 from an open state to a closed state.

[0034] [Inflow pipe section, first cylindrical section, second cylindrical section] As shown in FIGS. 4 to 6, the inflow pipe 76 includes a first cylindrical portion 76A, a second cylindrical portion 76B disposed downstream of the first cylindrical portion 76A, and a third cylindrical portion 76C connecting the first cylindrical portion 76A and the second cylindrical portion 76B. As shown in FIGS. 7 and 8A, the first cylindrical portion 76A is cylindrical. As shown in FIG. 8D, the second cylindrical portion 76B is cylindrical, with the rear portion of the internal space of the first cylindrical portion 76A eliminated. Specifically, a perpendicular surface 80 perpendicular to the axis extending in the front-rear direction is provided on the rear side of the inner circumferential surface of the second cylindrical portion 76B. When the inflow pipe 76 is cut horizontally, the cross-sectional area of ​​the internal space of the second cylindrical portion 76B is smaller than the cross-sectional area of ​​the internal space of the first cylindrical portion 76A (see FIGS. 8A and 8D). In this embodiment, the cross-sectional area of ​​the internal space of the second cylindrical portion 76B is approximately 80% of the cross-sectional area of ​​the internal space of the first cylindrical portion 76A. The internal space of the second cylindrical portion 76B is flatter in the front-to-rear direction than the internal space of the first cylindrical portion 76A.

[0035] [Third cylindrical part, connection surface] As shown in Fig. 6, the third cylindrical portion 76C has a smooth inner circumferential surface that continuously connects the first cylindrical portion 76A and the second cylindrical portion 76B. As shown in Figs. 8(A) to 8(C), the inner circumferential surface of the third cylindrical portion 76C is provided with a connection surface 81 that is located on the rear side in the second direction. Here, the second direction is the flow direction of hot water before it changes direction upward at the connection portion between the connecting pipe portion 70 and the inlet pipe portion 76, and corresponds to the right side in Fig. 5. The connection surface 81 is located further inward of the third cylindrical portion 76C as it moves from upstream to downstream (from bottom to top). The inner circumferential surface of the third tubular portion 76C, excluding the connecting surface 81, is a cylindrical inner circumferential surface that is continuously connected to the cylindrical inner circumferential surfaces of the first tubular portion 76A and the second tubular portion 76B.

[0036] In this embodiment, the flow direction of the hot water is changed from the second direction to upward at the connection portion (second bent pipe portion 70C) between the connecting pipe portion 70 and the inlet pipe portion 76. At this time, the hot water collides with the inner surface of the second bent pipe portion 70C (and the first cylindrical portion 76A) at the rear side in the second direction, forming a swirling flow, and is pushed out by the following hot water. As a result, the hot water introduced into the inlet pipe portion 76 tends to rise while swirling. The swirling flow here refers to a circular flow that follows the inner surface of the first cylindrical portion 76A. Furthermore, when the hot water is deflected upward from the second direction and enters the inlet pipe portion 76, the inertia of the hot water makes it more likely that the hot water will be biased toward the rear side in the second direction than the front side within the inlet pipe portion 76.

[0037] However, in this embodiment, a connection surface 81 is formed at the rear side in the second direction of the inner surface of the third tubular portion 76C, which slopes inward as it moves from upstream to downstream (as it moves upward).Therefore, the hot water that is on an upward trend rises while encountering resistance from this connection surface 81, and the swirling component of the hot water is gradually suppressed. Furthermore, because the connection surface 81 is disposed on the inner circumferential surface of the third cylindrical portion 76C at the rear in the second direction, the bias of the hot water toward the rear in the second direction is alleviated as the hot water flows upward (downstream). Therefore, according to this embodiment, even if the connection portion between the connection pipe portion 70 and the inflow pipe portion 76 is bent, the flow of hot water flowing into the detection chamber 75 can be stabilized, and the water flow switch 40 can be stably operated.

[0038] As shown in FIG. 8(B), the upstream end (lower end) of the connection surface 81 is provided with an upstream end surface 81A that is substantially perpendicular to the axis extending in the second direction. The upstream end surface 81A is formed facing the opposite side to the second direction. As shown in FIG. 7, the upstream end surface 81A narrows toward the upstream side (lower side) and disappears into a dot at the boundary between the third tubular portion 76C and the first tubular portion 76A. As shown in FIG. 4, the downstream end (upper end) of the connection surface 81 is substantially perpendicular to the axis extending in the front-rear direction and smoothly connects to the perpendicular surface 80 of the second tubular portion 76B. The downstream end of the connection surface 81 is formed facing forward. As shown in FIGS. 8(B) and 8(C), the connection surface 81 is formed inward of the third tubular portion 76C so that the facing direction of the connection surface 81 continuously changes from the direction opposite to the second direction to the forward direction from the upstream end surface 81A to the downstream end. In this embodiment, the normal vector of connecting surface 81 changes by about 30° in plan view (when viewed from the first direction) from the upstream end surface 81A to the downstream end. It is preferable that the angle change of the normal vector of connecting surface 81 in plan view is an acute angle.

[0039] As shown in Figure 3, hot water flows into the water flow switch 40 from the connecting pipe 70 in the second direction (diagonally rearward to the left) at a finite speed and flows out forward toward the piping 78. In other words, the flow direction of hot water upstream and downstream of the water flow switch 40 is offset by a finite angle in the horizontal plane. This can cause pressure loss and swirling flow of hot water inside the water flow switch 40. In this embodiment, the connection surface 81 has a smooth inner surface, and the facing direction of the connection surface 81 continuously changes from the direction opposite the second direction to the forward direction, thereby minimizing the pressure loss of hot and cold water inside the water flow switch 40 and making it easier to straighten the flow of hot and cold water.

[0040] [Effects of the embodiment] As described above, the bath heater 1A according to the embodiment is a bath heater 1A that is installed in a circulation circuit (bath circuit B) through which hot and cold water circulates, and includes a pump 38 that circulates hot and cold water in the circulation circuit, a water flow switch 40 that is arranged in the circulation circuit and operates in response to water flow in a first direction (upward), and a connecting pipe 70 that connects the pump 38 and the water flow switch 40. At the connection between the connecting pipe 70 and the water flow switch 40, the direction of hot and cold water flow changes from a second direction that intersects with the first direction to the first direction. The water flow switch 40 comprises a casing 71 that forms a path for hot and cold water, a detection piece 72 that is swingably provided in a detection chamber 75 formed in the casing 71, a fixing member 73 that fixes one end of the detection piece 72, and a reed switch 74 that is fixed to the casing 71 and is closed when the detection piece 72 approaches. The casing 71 has an inflow pipe section 76 through which hot and cold water that has flowed in from the connection pipe section 70 flows out into the detection chamber 75, and a reed switch 74 through which hot and cold water flows out from the detection chamber 75 in a third direction (forward) that is perpendicular to the first direction. The third direction intersects with the second direction. The inflow pipe portion 76 includes a first cylindrical portion 76A, a second cylindrical portion 76B disposed downstream of the first cylindrical portion 76A, and a third cylindrical portion 76C connecting the first cylindrical portion 76A and the second cylindrical portion 76B and having a smooth inner circumferential surface. The cross-sectional area of ​​the internal space of the second cylindrical portion 76B is smaller than the cross-sectional area of ​​the internal space of the first cylindrical portion 76A. The inner circumferential surface of the second cylindrical portion 76B is provided with an orthogonal surface 80 disposed on the opposite side of the third direction and orthogonal to the third direction. The intersecting surface 80 extends in a first direction from the upstream end of the second tubular portion 76B, and a connecting surface 81 is formed on the inner surface of the third tubular portion 76C, connecting the perpendicular surface 80 to the inner surface of the first tubular portion 76A.The connecting surface 81 is located inside the third tubular portion 76C, with the direction in which it faces continuously changing from the direction opposite the second direction to the third direction as it moves from upstream to downstream, and the upstream end of the connecting surface 81 is located at the back side of the inner surface of the third tubular portion 76C in the second direction.This is a bath heater 1A.

[0041] In the above configuration, hot water flows from the pump 38 through the connecting pipe 70 into the inlet pipe 76 of the water flow switch 40. At the connection between the connecting pipe 70 and the water flow switch 40, the flow direction of the hot water is biased from the second direction to the first direction. Therefore, a swirling flow of hot water is generated at the connection between the connecting pipe 70 and the water flow switch 40. The hot water that flows from the connecting pipe 70 into the inlet pipe 76 flows in the first direction within the first cylindrical portion 76A of the inlet pipe 76, biased toward the back side in the second direction. Furthermore, the flow of hot and cold water changes from the second direction to the third direction upstream and downstream of the water flow switch 40, which also creates a drift and swirling flow of hot and cold water.

[0042] The inner peripheral surface of the third cylindrical portion 76C is provided with a connection surface 81 that is positioned inward of the third cylindrical portion 76C as it moves from upstream to downstream. This suppresses the swirling flow of hot and cold water as it flows in the first direction inside the third cylindrical portion 76C. The cross-sectional area of ​​the internal space of the second cylindrical portion 76B is also smaller than the cross-sectional area of ​​the internal space of the first cylindrical portion 76A. Therefore, the flow of hot and cold water is easily straightened as it passes through the interiors of the third cylindrical portion 76C and the second cylindrical portion 76B. This stabilizes the flow of hot and cold water in the detection chamber 75, allowing the hot and cold water to be pressurized in a concentrated manner at a fixed position on the detection piece 72. As a result, the water flow switch 40 can be operated stably.

[0043] Furthermore, the connecting surface 81 continuously changes the facing direction from the direction opposite the second direction to the third direction as it moves from upstream to downstream, so that the pressure loss of hot water caused by flowing within the third tubular portion 76C can be minimized while rectifying the hot water.

[0044] In this embodiment, the cross-sectional area of ​​the internal space of the second cylindrical portion 76B is preferably equal to or greater than half the cross-sectional area of ​​the internal space of the first cylindrical portion 76A.

[0045] In the above configuration, the cross-sectional area of ​​the internal space of the second cylindrical portion 76B is more than half the cross-sectional area of ​​the internal space of the first cylindrical portion 76A, so the second cylindrical portion 76B and the third cylindrical portion 76C can straighten the flow of hot water while reducing pressure loss of the hot water.

[0046] The water heater 1 with a bath heater in this embodiment is a water heater 1 with a bath heater, comprising a bath heater 1A, a water heater circuit A, and a burner 6 that heats a bath heat exchanger (bath primary and secondary heat exchangers 13, 14) provided in the circulation circuit (bath circuit B) and a water heater heat exchanger (water heater primary and secondary heat exchangers 11, 12) provided in the water heater circuit A.

[0047] <Other embodiments> (1) In the embodiment, the water heater 1 with the bath heater 1A is illustrated, but the bath heater may not be provided in combination with the hot water supply circuit.

[0048] (2) In the embodiment, the connecting portion between the connecting pipe portion 70 and the inflow pipe portion 76, where the hot water changes direction from the second direction to the first direction, was the second bent portion 70B of the connecting pipe portion 70, but the connecting portion where the hot water changes direction from the second direction to the first direction may be provided in the inflow pipe portion. For example, the inflow pipe portion may be cylindrical with a bottom, and the connecting pipe portion may be inserted into a through hole provided in the side wall of the inflow pipe portion.

[0049] (3) In the embodiment, the connecting pipe 70 includes the straight pipe 70B extending horizontally and the first and second bent pipes 70A and 70C. However, the connecting pipe may have a shape extending in a direction intersecting the first direction at the end of the inlet pipe. For example, the straight pipe of the connecting pipe may be slightly inclined with respect to the horizontal. The connecting pipe may also be curved. [Explanation of symbols]

[0050] 1: Water heater with bath heater, 1A: Bath heater 2: Inner body, 3: Partition member, 4: Hot water supply combustion chamber, 5: Bath combustion chamber, 6: Burner, 6A: Hot water supply burner, 6B: Bath burner, 8: Spark plug, 9: Flame rod, 10: Combustion fan, 11: Hot water supply primary heat exchanger, 12: Hot water supply secondary heat exchanger, 13: Bath primary heat exchanger, 14: Bath secondary heat exchanger, 15: Exhaust hood, 16: Exhaust port, 17: Gas pipe, 18: Gas branch pipe, 19: Gas solenoid valve, 20: Main gas solenoid valve, 21: Gas proportional valve, 22: Water supply pipe, 23: Strainer, 24: Hot water supply water volume sensor, 25: Hot water supply inlet thermistor, 26: Water volume control motor, 27: Hot water outlet pipe, 28 :Hot water heat exchanger thermistor, 29:Hot water outlet thermistor, 30:Bypass pipe, 31:Water distribution valve, 35:Return pipe, 36:External return pipe, 37:Bathtub, 38:Pump, 39:Bath return thermistor, 40:Water flow switch, 41:Water level sensor, 42:Supply pipe, 43:External supply pipe, 44:Bath supply thermistor, 45:Drop-in pipe, 46:Drop-in water solenoid valve, 47:Bath water level sensor, 48:Check valve, 49:Shut-off valve, 50:Drain pipe, 51:Inlet pipe, 55:Neutralizer, 56:Drain receiver, 57:Drain inlet pipe, 58:Drain discharge pipe, 59:Water level electrode, 60:Drain outlet 70: connecting pipe section, 70A: first bent pipe section, 70B: straight pipe section, 70C: second bent pipe section 71: casing, 71A: casing body, 71B: lid, 72: detection piece, 72A: elastic piece, 72B: magnetic body, 73: fixing member, 74: reed switch, 75: detection chamber 76: inlet pipe section, 76A: first cylindrical section, 76B: second cylindrical section, 76C: third cylindrical section, 77: outlet pipe section, 78: piping, 80: perpendicular surface, 81: connection surface, 81A: upstream end surface A: Hot water circuit, B: Bath circuit (circulation circuit)

Claims

1. A bath heater configured to include a part of a circulation circuit through which hot water circulates, a pump that circulates hot and cold water through the circulation circuit; a water flow switch disposed in the circulation circuit and operable in response to a water flow in a first direction; a connecting pipe portion that connects the pump and the water flow switch, At a connection portion between the connecting pipe portion and the water flow switch, the flow direction of hot and cold water changes from a second direction intersecting the first direction to the first direction, The water flow switch comprises a casing that forms a path for hot and cold water, a detection piece that is swingably provided in a detection chamber formed in the casing, a fixing member that fixes one end of the detection piece, and a reed switch that is fixed to the casing and is closed when the detection piece approaches. The casing includes an inlet pipe section through which hot and cold water flowing in from the connecting pipe section flows out into the detection chamber, and an outlet pipe section through which hot and cold water flows out from the detection chamber in a third direction perpendicular to the first direction, the third direction intersects with the second direction, The inlet pipe portion is a first cylindrical portion having a cylindrical shape; a second cylindrical portion disposed downstream of the first cylindrical portion; a third cylindrical portion that connects the first cylindrical portion and the second cylindrical portion and has a smooth inner circumferential surface, a cross-sectional area of ​​the internal space of the second cylindrical portion is smaller than a cross-sectional area of ​​the internal space of the first cylindrical portion; an orthogonal surface that is disposed on the opposite side of the third direction and is orthogonal to the third direction is provided on an inner circumferential surface of the second cylindrical portion; the orthogonal surface extends in the first direction from an upstream end of the second cylindrical portion, a connecting surface that connects the orthogonal surface and the inner circumferential surface of the first cylindrical portion is formed on an inner circumferential surface of the third cylindrical portion, the connecting surface is located inside the third cylindrical portion while the facing direction of the connecting surface continuously changes from a direction opposite to the second direction to the third direction as the connecting surface moves from upstream to downstream, A bath heater in which the upstream end of the connection surface is arranged at the rear side of the inner surface of the third cylindrical portion in the second direction.

2. The bath heater according to claim 1, wherein the cross-sectional area of ​​the internal space of the second cylindrical portion is at least half the cross-sectional area of ​​the internal space of the first cylindrical portion.

3. The bath heater according to claim 1 or claim 2, A hot water circuit; A water heater with a bath heater, comprising: a burner for heating a bath heat exchanger provided in the circulation circuit and a hot water heat exchanger provided in the hot water circuit.

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